Final validation of the results was done with ddPCR, a technology that can detect mosaicism with a sensitivity as low as 0.001%.(25) To our knowledge, the AMER1 deletion in patient 1 is the first mosaic mutation described in a female patient with a diagnosis of OSCS, and the mosaic RUNX2 deletion in patient 2 is the second description of a mosaic deletion in an individual affected by CCD. The gene discussed is AMER1; the disease is osteopathia striata with cranial sclerosis.